This invention relates to improvements in the cooking of a food product in the presence of a radiant energy source and, more particularly to an apparatus for the uniform heating of a food product in a radiant energy field.
The use of radiant energy for cooking, particularly in connection with a microwave oven, has become widespread in recent years. An estimated 66% of the 88 million American households now have microwave ovens and, in the post World War II period, microwaves have been the fastest growing appliance tracked by the Association of Home Appliance Manufacturers. Microwave cooking has reached this level of popularity primarily because food can be heated quickly and conveniently without the fuss of a lengthy meal preparation. However, the energy in a microwave oven is not distributed equally throughout the cavity of the oven. This unequal distribution causes some areas in the oven to be warmer than others and, as a consequence, food in those areas becomes hotter resulting in significant temperature differences between portions of food or within a single portion of food.
Many attempts have been made to equalize heat in the food. For example, stirring helps, but there are many foods that cannot be stirred. Rearranging, or rotating, the food within the oven cavity could help, but the food generally must be moved often to cook even substantially uniformly, a procedure that greatly reduces the convenience aspect of microwave cooking.
Reflective cells, as in parent U.S. Ser. No. 765,374, provide movable reflectors for reflecting the microwaves. The reflectors are movable with variations in the response of a temperature sensor, so that the reflectors vary the direction of the reflected microwave relative to the food product and vary the concentration of the reflective microwaves incident on the food to promote uniform heating.
The simplified apparatus of the present invention provides certain desirable advantages not obtained, with the apparatus of parent U.S. Ser. No. 765,374, now U.S. Pat. No. 4,683,362. For example, the apparatus of the present invention can be used in connection with a conventional radiant energy source such as a microwave oven or in connection with a commercial conveyor belt system wherein the food product is placed on trays, formed by the apparatus, and the trays are thereafter passed through a radiant field. This application is useful in a commercial cooking environment such as an institution or in the production of precooked food products.
As in parent U.S. Ser. No. 765,374, now U.S. Pat. No. 4,683,362, the collectors can be formed from a bimetallic material. The bimetallic material will fluctuate in relation to heating and cooling and vary the energy field radiating from the apparatus to promote uniform heating of the food product.